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Breach occurred 2011-12-21Verifiedcsdn.net
What happened
In 2011, the China Software Developer Network (CSDN) suffered a data breach that exposed over 6M user records. The data included email addresses alongside usernames and plain text passwords.
Data exposed
Frequently asked questions
The China Software Developer Network data breach occurred on December 21, 2011. It was added to Have I Been Pwned's breach catalog on November 27, 2025.
6,414,990 accounts were affected by the China Software Developer Network data breach, according to Have I Been Pwned's records.
The China Software Developer Network breach exposed the following data types: Email addresses, Passwords, Usernames.
Yes. Have I Been Pwned has verified the China Software Developer Network breach, meaning there's confirmed evidence the exposed data is genuine and tied to real accounts.
Use KazaSec's free Email Breach Checker (/tools/breach-check) to check whether a specific email address has surfaced in the China Software Developer Network breach, or any other known breach — the tool never stores what you search.
Our free Email Breach Checker tells you whether a specific email address has surfaced in this breach — or any other known breach — without ever storing what you search.
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